unit 1 physics lisachem 2008

Learning Materials by Lisachem VCE Physics 2008 Year 11 Trial Exam Unit 1

VCE PHYSICS 2008

YEAR 11 TRIAL EXAM UNIT 1 CONDITION OF SALE: © Limited copyright. This paper may be photocopied without charge for use only within the school that has purchased the material. Our electronic copy only may be placed on the school intranet for the exclusive use by the teachers and students of the school that has purchased the material. They may not otherwise be reproduced (all or part) electronically, scanned into a school computer, forwarded via email, or placed on the Internet, without written consent of the publisher.

Reading Time: 15 minutes Writing Time: 90 minutes Structure of Booklet

Section No of

Questions No of Questions to

be answered No of Marks

A. Core Area of Study 1. Wave-like Properties of Light 2. Nuclear & Radioactivity Physics

20 14

20 14

40 25

B. Detailed Study 1. Astronomy 2. Medical Physics 3. Energy from the Nucleus

10 10 10

10 10 10

20 20 20

Students are permitted to bring into the examination room: pens, pencils, highlighters, erasers, sharpeners, rulers, up to two pages (one A4 sheet) of pre-written notes (typed or handwritten) and an approved graphics calculator (memory cleared) and/or one scientific calculator. Students are not permitted to bring into the examination room: blank sheets of paper and/or white out liquid/tape. Materials Supplied Question and answers booklet with detachable formula sheet. Instructions Detach the formula sheet during reading time. Write your name in the space provided. Answers all questions in the question and answers booklet when indicated. Also show your workings where space is provided. Where an answer box has a unit printed in it, give your answer in that unit. All responses must be in English.

Learning Materials by Lisachem PO Box 2018, Hampton East, Victoria, 3188

Ph: (03) 9598 4564 Fax: (03) 8677 1725 Email: [email protected] or [email protected]

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Data Sheet VCE Physics 2008 Year 11 Unit 1

1 velocity; frequency, wavelength v f λ=

2 distance, velocity, time

x vt=

3 frequency; period

1fT

=

4 reflection of light;

i r=

5 mirrors

1 1 1v u f+ =

6 Snell’s law

sinsin

i constantr=

2

1

sin cnin

=

1 2

9

6

3

3

6

9

3

p = p ico = 1 0n = n an o = 1 0

µ = m ic ro = 1 0m = m illi = 1 0

k = k ilo = 1 0M = m eg a = 1 0G = g ig a = 1 0

1 to n n e = 1 0 k g

−

−

−

−

P re f ixe s /U n its

Learning Materials by Lisachem VCE Physics 2008 Year 11 Trial Exam Unit 1

VCE Physics 2008 Year 11 Trial Exam Unit 1 Section A: Core

Instructions for Section A Answer all questions for both Areas of study in this section of the paper. Area of Study 1: Wave-like Properties of Light Questions 1 to 2 refer to the following information. Figure 1 shows water waves passing Linda who is standing in the water.

Figure 1 In 5.0 seconds, 5 waves go past her. Question 1 Calculate the frequency of the water waves.

(2 marks)

Hz

Water waves are transverse waves. Question 2 Give one other example of a transverse wave. __________________________________________________

(1 mark)

Learning Materials by Lisachem VCE Physics 2008 Year 11 Trial Exam Unit 1 1

Question 3 Describe a longitudinal wave in terms of; particle vibration, compressions, rarefactions and direction of energy flow. Give an example of energy that flows by longitudinal wave motion. __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________

(3 marks) Figure 2 shows a shape in front of a plane mirror.

Mirror

Figure 2

Question 4 Carefully draw the position of the image on the diagram above.

(2 marks) Questions 5 and 6 refer to the following information in Figure 3. An object is placed 9.0 cm in front of a concave mirror. The mirror has a focal length of 6.0 cm.

15 10 5 0

0

Mirror

Figure 3


Question 5 Use construction lines to locate the position of the image.

(2 marks) Question 6 Describe the nature, orientation and magnification of the image __________________________________________________

(2 marks) Questions 7 to 9 refer to the following information. An object is placed 6.0 cm in front of a convex mirror. The mirror has a focal length of 4.0 cm. Question 7 Use the mirror equation to find the distance of the image from the mirror.

(2 marks) Question 8 Calculate the magnitude of the magnification of the image.

(2 marks) Question 9 Which of the following, A – D, correctly describes the image that is produced? A. Upright, virtual, enlarged. B. Upright, virtual, diminished. C. Upright, real, enlarged. D. Inverted, real, diminished.

(2 marks)

cm


Questions 10 and 11 refer to the following information. The diverging lens in Figure 4 forms an image of the object, O.

F1 F2

Object

Figure 4

Question 10 Use Figure 4 to produce a ray diagram to locate, and label, the image I, of the object.

(2 marks) Question 11 Describe the nature, orientation and magnification of the image. __________________________________________________ __________________________________________________

(2 marks) Questions 12 to 15 refer to the following information. Figure 5 shows an object of height 2.0 cm, placed 10 cm from a convex lens. The lens has a focal length of 20 cm.

Figure 5

20 2010 100

Object

Question 12 Use a ray tracing diagram to locate the image, I, formed.

(2 marks)


Question 13 Which one of the following, A – D, best describes the image formed? A. Real, upright, enlarged. B. Real, inverted, diminished. C. Virtual, upright, enlarged. D. Virtual, inverted, diminished.

(2 marks)

Question 14 Use the lens equation to calculate the distance the image is from the lens?

(2 marks)

cm

Question 15 Calculate the magnification of the image.

(2 marks)

M =

Questions 16 and 17 refer to the following information. Crown glass is commonly used in lens’ and prisms found in optical instruments and has an absolute refractive index of 1.5. Question 16 Calculate the critical angle for light travelling from crown glass into air.

(2 marks)

°


Two 45°crown glass prisms are used in submarine periscopes. Figure 6 is a simplified diagram of how the two prisms are employed. The light is incident on the side of the prism at an angle of 90° to the surface.

45° rays 90°

Figure 6 Question 17 Explain why total internal reflection occurs at each of the prism’s long face. __________________________________________________ __________________________________________________

(2 marks) A narrow beam of white light is passed through a triangular prism but this time, the light is separated into a band of colours. Glass has absolute refractive indices for red and violet light of n = 1.51 and n = 1.53 respectively. Air has a refractive index of n = 1.000 for both colours. Question 18 Calculate the angle of refraction for red light passing from glass to air if the angle of incidence is 40°. °

(2 marks)

°


Question 19 Identify the two types of dispersion of light that occur in light transmission through optical fibres.

Description of dispersion Type of dispersion Light of different colour travels at different speeds through transparent material. Red light travels faster than violet light and the signal is spread.

Axial rays, with the shortest path length, will have the shortest transmission time, while rays entering the fibre at its maximum acceptance angle will travel further and require the maximum time.

(2 marks) A blue wall is illuminated with a monochromatic red lamp. Question 20 What colour does the blue wall appear when the red lamp illuminates it? Justify your answer. __________________________________________________ __________________________________________________

(2 marks)

End of Area of Study 1

Section A: Continued


Section A: Continued Area of Study 2: Nuclear and Radioactive Physics Questions 1 to 3 refer to the following information. Three types of radiation with different properties are given in Table 1.

Type of radiation

Symbol Penetrating ability

Ionizing ability

Nature of radiation

alpha

42 He

very high helium nucleus

beta

moderate Electron

gamma

00γ Very high very low

Table 1 Question 1 Complete Table 1 by inserting the missing information.

(2 marks) One type of radiation is ‘fired’ into a region with an electric field. On entering the field, the path of the radiation changes as shown in Figure 1.

+ - electric field + - + - + - + -

radiation path

Figure 1 Question 2 What is the charge, if any, possessed by the radiation?

(1 mark)


Question 3 Identify the type of radiation.

(1 mark)

The nuclide is radioactive and one product of its decay is 23 . 23491Pa 4

92 U Question 4 Complete the decay equation and name the type of radiation produced. + ______________________ 234

91Pa 23492 U

(2 marks) Questions 5 and 6 refer to the following information A radio isotope of the element Nitrogen, , has a half-life of 10 minutes. Initially, a sample consists of 8.8 g of .

N137

N137

Question 5 Calculate the quantity, in g, of that remains after 30 minutes. N13

7

(2 marks)

g

Question 6 What period of time, in minutes, has elapsed when there is only 0.55 g of nitrogen-13 remaining?

(1 mark)

minutes


Questions 7 and 8 refer to the following information Uranium – 234, , is a radioactive isotope. Figure 2 shows the number of protons and neutrons in the nuclei of the nuclides that are formed when uranium – 234 decays.

23492 U

Number of neutrons 143 142 141 140 139 138 137 87 88 89 90 91 92 93 94 Number of protons

Figure 2

234U

230Th

226Ra

Question 7 Explain how Figure 2 shows that two alpha particles are emitted when 234U decays to 22 . 6Ra__________________________________________________ __________________________________________________ __________________________________________________

(2 marks) Radioactive decay is usually accompanied by gamma radiation. Question 8 Explain why gamma emission only from a radio isotope does not cause a new isotope to be formed. __________________________________________________ __________________________________________________

(2 marks)


Igneous rock contains , which eventually changes to the stable isotope, . Figure 3 shows how the percentage of uranium-238 nuclei present in a sample of igneous rock changes with time.

238 U 206 Pb

percentage of uranium-238 100 90 80 70 60 50 40 30 20 10 0 0 2.0 4.0 6.0 8.0 10 years ( ) 910×

Figure 3 An igneous rock sample is found to contain six atoms of uranium-238 for every four atoms of lead-206. Question 9 Use the graph to estimate the age, in years, of the rock. Show your working out clearly.

(2 marks)

years


Questions 10 to 12 refer to the following information. A cancer patient with a mass of 70 kg absorbs 0.20 J of energy due to ionising radiation. Table 2 gives the quality factors for different types of ionising radiation.

Type of radiation Approximate quality factor

β particles 1 γ rays 1 α particles 10 Slow neutrons 3 Fast neutrons 10

Table 2

Question 10 Calculate the patient’s absorbed dose in Gy.

(2 marks)

Gy

Question 11 Calculate the dose equivalent, in Sv, if the energy was delivered by gamma rays.

(2 marks)

Sv

Question 12 Which would cause more damage: a dose of 0.05 Sv ofγ rays or a dose of 0.05 Sv of particles? Justify your answer.

α

__________________________________________________ __________________________________________________

(2 marks) Neutrons can be detected by allowing them to be captured by boron-10 nuclei in a counter (similar to a Geiger counter) but filled with 10 gas. nuclei are produced in the reaction.

3BF 73Li

Question 13 Complete the nuclear reaction and identify the other product.

1 10 70 5 3n + B Li +→

__________________________________________________

(2 marks)


9 9 m4 3T c is an isotope of technetium that is used in medical imaging. 9 9 m

4 3T c .The initial activity of a sample of is 16 × 109 becquerel (Bq), which subsequently changes with time as shown in Figure 4.

9943Tcm

Activity ( Bq) 910× 20 18 16 14 12 10 8.0 6.0 4.0 2.0 0 0 2 4 6 8 10 12 14 16 18 time (hr)

Figure 4 Question 14 Determine the half-life, in hr, of technicium-99m.

(2 marks)

hr

End of Area of Study 2

End of Section A


Section B: Detailed Study Instructions for Section B

Choose one of the following Detailed Studies. Answer all the questions on the Detailed study you have chosen.

Detailed Study 1: Astronomy

Declination (degrees) +30 +20 +10 8 7 6 right ascension (hours)

Figure 1

Castor

Pollux

ecliptic

Figure 1 shows the constellation of Gemini. Castor and Pollux, the two brightest stars, are labeled. Question 1 Give the approximate co-ordinates of Pollux. Right ascension: _______________________________________ Declination: _______________________________________

(2 marks) Question 2 From which latitude on Earth could Castor be seen directly overhead?

(1 mark) Figure 1 shows the ecliptic line.


Question 3 Describe the astronomical significance of the ecliptic on a star chart. __________________________________________________ __________________________________________________

(2 marks) Question 4 On Figure 1, show the position of the Sun, with letter “S”, on June 21st.

(1 mark)

Stars are said to possess ‘diurnal’ motion. Question 5 Explain the meaning of diurnal motion. __________________________________________________ __________________________________________________

(2 marks) Very few observations are made any more by astronomers looking directly through optical telescopes. Question 6 Explain the meaning of this statement. How then is astronomical information obtained. __________________________________________________ __________________________________________________ __________________________________________________

(3 marks) X-ray telescopes can be employed in space and also from aircraft. Question 7 Can ground-based X-ray telescopes be used? Justify your answer. __________________________________________________ __________________________________________________ __________________________________________________

(3 marks)


Question 8 Complete the table indicating two similarities and differences between radio telescopes and reflecting telescopes.

Similarities Differences Radio telescopes and reflecting telescopes

_______________

_______________

_______________

_______________

_______________

_______________

(2 marks) Question 9 Describe what an equatorial mounting of a telescope is, and why it is useful. __________________________________________________ __________________________________________________

(2 marks) Question 10 Ptolemy's geocentric theory was preferred to Copernicus' heliocentric theory before the advent of Kepler and Galileo. From the choices, A – D, select the best alternative reason why this was so. A The geocentric theory accounted for the same observed motions of the planets as the

heliocentric theory, but better matched the philosophy of the time; B The geocentric theory accounted for retrograde motion, which the heliocentric theory

was unable to explain; C The heliocentric theory used complex constructions called epicycles and deferents to

account for the observed motions of the planets, and so was considered more reliable than the geocentric theory;

D The heliocentric theory was obviously incorrect from watching the Sun move.

(2 marks)

End of Detailed Study 1


Detailed Study 2: Medical Physics Table 1 gives information about 6 radioisotopes.

Isotope type of radiation emitted

half - life

hydrogen-3 beta particle 12 years iridium-192 gamma ray 74 days

polonium-210 alpha particle 138 days polonium-213 alpha particle 0.90 seconds technetium-99 gamma ray 6 days uranium-239 beta particle 24 minutes

Table 1

A doctor needs to monitor blood flow through a patient’s heart. The doctor injects a radioisotope into the patient’s bloodstream. The radiation emitted by the isotope can be detected outside the patient’s body. Question 1 Which one of the isotopes in Table 1 would be most suitable for this purpose? Justify your choice. __________________________________________________ __________________________________________________

(3 marks) Figure 1 shows how radiation can be used to kill the cells of a brain tumour.

skull tumour radioactive source

top view

Figure 1 Question 2 Explain why a beta particle emitting radiation source would be unsuitable for this purpose. __________________________________________________ __________________________________________________ __________________________________________________

(2 marks)


Questions 3 and 4 refer to the following information. The image in Figure 2 shows a brain tumour. The PET is very useful not only in detecting a tumour when it is in the initial stages of growth, making the treatment more effective in eradicating it, but also for detecting its type, malignancy and spread.

Figure 2 Question 3 What does the word “PET” refer to in medical physics? __________________________________________________

(1 mark) A PET scan is an example of non-invasive diagnosis. Question 4 Explain the meaning of non-invasive diagnosis. ____________________________________________________________________________________________________

(2 marks) PET produces images of the body by detecting the radiation emitted from radioactive substances. These substances are injected into the body, and are usually tagged with a radio isotope, such as carbon-11, fluorine-18, oxygen-15, or nitrogen-13, that has a short half life. Question 5 Why must PET diagnostic centres be located near a particle accelerator device that produces the radioisotopes used in this technique? __________________________________________________ __________________________________________________ __________________________________________________

(3 marks)


Figure 3 shows a pre-natal scan obtained using ultrasonic sound waves (ultrasound).

Figure 3 Question 6 Explain how ultrasonic sound waves are used to produce images. __________________________________________________ __________________________________________________ __________________________________________________

(2 marks) Questions 7 and 8 refer to the following information. Endoscopes are used in many surgical procedures. An endoscope may use light from a filament lamp and light from a laser. Question 7 In what way is the light from a filament lamp used in an endoscope? __________________________________________________

(1 mark) Question 8 In what way is the light from a laser used in an endoscope? __________________________________________________

(1 mark)


Figure 4 shows a number of images of human tissue obtained by three means; endoscopy, thermography and X-ray (in no particular order).

Image A

Image B

Image C

Figure 4 Question 9 Complete Table 2 by inserting the correct method of image formation and the part of the electromagnetic spectrum used to form the image.

Method

Image

Type of electromagnetic radiation used

Endoscopy Thermography X-ray

(3 marks) Table 2

Microwaves are used to send information within mobile phone networks. Question 10 Explain how microwaves could affect living cells. __________________________________________________ __________________________________________________

(2 marks)



Detailed Study 3: Energy from the Nucleus Table 1 shows the observed effects of various types of forces. Question 1 Complete the table by inserting the name of the force responsible for the observed effects. Observation Force responsible Attraction between all objects in the universe Holding the atom together Holding the nucleus together

Table 1

(3 marks) Question 2 Which one of the following is an example of nuclear fission? A. A plutonium nucleus splitting into two smaller nuclei. B. A boron nucleus absorbing a neutron. C. A uranium nucleus emitting a neutron. D. Two deuterium nuclei forming a helium nucleus. 2

H1

⎛ ⎞⎜ ⎟⎜ ⎟⎝ ⎠

(2 marks)

Question 3 Which one of the following statements is correct? A. Nuclear fission is more likely to occur between small nuclei. B. It is possible to fission any nucleus provided that the bombarding particles have

enough kinetic energy. C. All radioactive nuclei are fissile. D. Only a few nuclei are fissile.

(2 marks)


Uranium-235 nucleus can capture a “thermal” neutron which has the right amount of kinetic energy. The neutron gives the nucleus enough energy to vibrate, which could make the nucleus ‘neck’. These processes are shown in Figures 1A and 1B, resulting in separation of the parts, Figure 1C.

neutron

A

neck B

C

Figure 1

Question 4 Name this process and explain the process in terms of forces between nucleons. __________________________________________________ __________________________________________________ __________________________________________________

(3 marks)

Uranium-238 may absorb a thermal neutron with the formation of lanthanum-140, bromine-97 and neutrons as given in the nuclear equation;

238 1 140 9792 0 57 35U + n La + Br + neutrons + energy→ .

Question 5 Calculate the number of neutrons released in this reaction.

(2 marks) number of neutrons =

Question 6 Select the correct alternative from A – D. A chain reaction occurs when: A. a neutron smashes up three nuclei; B. a few neutrons are released, each of which goes on to be captured by other nuclei,

causing them to fission; C. A chemical reaction has occurred.; D. the three neutrons that are released fuse together, producing lots of energy.

(2 marks)


Questions 7 and 8 refer to the following information. Nuclear reactors are used to produce electricity. The kinetic energy of the fission fragments and neutrons are transformed to thermal energy. In one breeder reactor, uranium-238 ( ) is converted in a series of steps to plutonium-239 ( ).

23892 U

23994 Pu

Question 7 How many neutrons are involved in the transformation of uranium-238 into plutonium-239?

(1 mark) Question 8

number of neutrons

Question 8 How many beta particles ( ) are involved in decay processes? 0

1e−

(1 mark)

Number of beta particles

An example of a fusion reaction is; 2 3 4 11 1 2 0H + H He + n + 18MeV→ .

This reaction will occur at a temperature of 72.0×10 C . Question 9 Explain why there are no nuclear fusion reactors producing electricity in the world today. __________________________________________________ __________________________________________________ __________________________________________________

(2 marks) Fusion reactors, if they could be made to work, would have a number of advantages over fission reactors: Question 10 State two advantages of fusion reactors over fission reactors. __________________________________________________ __________________________________________________ __________________________________________________

(2 marks)


End of Trial Exam


Suggested Answers VCE Physics 2008 Year 11 Trial Exam Unit 1 Question Section A: Core Suggested

Mark Allocation

Area of Study 1: Wave-like Properties of Light Question 1 The period of the wave is 1.0 s.

Use: 1T = f

f = 1.0 Hz

1 1

Question 2 Electromagnetic waves and water waves are transverse waves. 1 Question 3 The particles of a medium vibrate parallel to the direction in

which the wave is traveling, causing regions of high pressure (compression) and low pressure (rarefaction). Sound energy

2 1

Question 4 The image is virtual and should be oriented as shown.

2

Question 5

2

Question 6 The image is real, inverted and enlarged. 2

Image

15 105 0

0

Mirror

Learning Materials by Lisachem Suggested Answers VCE Physics 2008 Year 11 Trial Exam Unit 1 1

Question 7 Using the Cartesian co-ordinate convention;

u = -6.0cmf = 4.0cmTo find v;1 1 1+ =v u f1 1 1= -v 4.0 -6.0

-10=-24

v = 2.4 cm

1

1 Question 8 Magnification, M:

-vM=u

-2.4-6.0

=0.40

⎛ ⎞⎜ ⎟⎝ ⎠

1 1

Question 9 Answer: B 2 Question 10

F1 F2

Object

Image

2

Question 11 The image is upright, virtual and diminished 2 Question 12

2

Question 13 Answer: C 2

20 2010 100

ObjectImage


Question 14 Use the Cartesian convention;

1 1 1- =v u fu = -10 cmf = 20 cm1 1 1 = +v 20 -1v = -20 cm

0

The image is 20 cm from the lens.

1

1

Question 15

magnification, M; -vM=u

-20=-10

=2.0

1

1 Question 16 Use the formula;

2C

1

C

nsini =n

1.0=1.5

i = 42°

1 1

Question 17 Light enters the faces of the prisms normally and falls on the hypotenuse face internally at an angle of incidence of 45°. Total internal reflection occurs since the critical angle for the glass is about 42°.

1

1 Question 18 Use the relation;

1 20

0

n sini=n sinr

1.51×sin40sinr=1.000

r=76

1 1

Question 19

Material dispersion. Modal dispersion.

1 1

Question 20 A blue wall will reflect blue light but absorb other colours. Red light will be absorbed, so the wall will appear black

1 1


Area of Study 2: Nuclear and Radioactive Physics Question 1

Type of radiation

symbol Penetrating ability

Ionizing ability

Nature of

radiation alpha

42 He very low

very high

helium nucleus

beta

0-1or eβ

moderate moderate electron

gamma

00γ very high very low electro

magnetic radiation

2

Question 2 The path of the radiation is curved toward the plate with the positive charge. The radiation must have a negative charge.

1

Question 3 The radiation is likely to be a beta particle. 1 Question 4 Balancing mass number and atomic number gives

23491Pa + + energy beta particle234

92 U 0-1e .

1 1

Question 5

The half-life is 10 minutes. 30 minutes is 3 half-lives. 8.8 g 4.4 g 2.2 g 1.1 g remains

1 1

Question 6 After one more half-life, there will be 0.55 g of the original isotope. This will be 4 half-lives or 40 minutes isotope. This will be 4 half-lives or 40 minutes.

1

Question 7 The isotopes; and differ in mass by 8 units and in atomic number by 4 units. These values indicate that 2 alpha particles are emitted in the decay.

23492 U 226

88 Ra 1

1 Question 8 Gamma radiation is electromagnetic radiation and is not a

charged particle. The emission of gamma rays from a nucleus results in no change to either the atomic number or the mass number.

1

1 Question 9 6 atoms of uranium-238 and 4 atoms of lead-206 gives 10 atoms

in total. So the % of uranium-238 in this sample is 60%. From the graph, 60% uranium-238 corresponds to an age of 3.0 x 10 9 years.

1 1

Question 10 Absorbed dose;

3

3

Jkg0.2070

2.86 102.9 10 Gy

−

−

=

=

= ×

= ×

1

1


Question 11 Dose equivalent;

= Gy x quality factor 3

3

2.86 10 12.9 10 Sv

−

−

= × ×

= ×

1 1

Question 12 The damage would be the same. Dose equivalent takes into account the nature of the radiation.

1

1 Question 13 1 10 7 4

0 5 3 2n + B Li + He→ the product required is an alpha particle.

1 1

Question 14 The starting count is 16 x 109 Bq. After one half-life, the count will be 8.0 x 109 Bq. From the graph, this corresponds to a time of 6.0 hr.

1 1

Detailed Study 1: Astronomy Question 1 Reading the co-ordinates from the graph;

Right ascension: 7.75 hr. Declination: +27o .

1 1

Question 2 Castor could be seen directly overhead at latitude +320.(N). 1 Question 3 The ecliptic is the path traced out by the sun over one year. 2 Question 4 The position of the sun is on the ecliptic at 6 hr RA. 1 Question 5 The entire sky appears to turn around imaginary points in the

northern and southern sky once in 24 hours. This is termed the daily or diurnal motion of the celestial sphere.

1 1

Question 6 Advances in technology have produced many new types of instrument for astronomical observation. Radio telescopes, X-ray telescopes, the Hubble telescope and attachments to telescopes preclude the need to only spend time in actual viewing.

1 1 1

Question 7 X-ray telescopes cannot be used on the ground. Most of the X-rays arriving at Earth are absorbed by the atmosphere before reaching the ground.

1 1 1

Question 8 Similarities: detect electromagnetic radiation; focus the radiation using a curved dish or mirror. Differences: radio telescopes are much larger than reflecting telescopes; radio telescopes do not necessarily require clear sky.

1

1

Question 9 The mounting of a telescope, allowing it to rotate around an axis parallel to that of the Earth. It keeps the star in view by rotating the telescope at exactly the same rate as the Earth rotates. Without this, any star being viewed quickly moves across the field of view and out of sight.

1

1

Question 10 Answer: A. 2 Detailed Study 2: Medical Physics Question 1 The most appropriate isotope to use would be technetium-99.

The half-life is suitable. Gamma ray emission is necessary if it is to be detected outside the body.

1 1 1


Question 2 A Beta particle emitting source would be unsuitable for this

purpose as beta particles cannot penetrate the skull bone to irradiate and kill tumour cells.

1 1

Question 3 PET is an acronym for “positron emission tomography”. 1 Question 4 A diagnosis involves detecting the presence and extent of a

problem. Invasive methods involve opening the pertinent part of the body through surgery. Non-invasive procedures involve non-surgical procedures for diagnosis.

1

1

Question 5 All the isotopes used are short-lived. A large amount would have to be produced if transport of the isotopes was necessary. PET diagnostic centres must be close to particle accelerators to reduce costs and for convenience.

1 1 1

Question 6 Ultrasonic sound waves travel at different speeds in different body tissue. The waves are reflected off the various tissues and arrive back at the source at different times. A picture can be electronically formed from the reflected signals.

1

1

Question 7 An endoscope uses light from a filament lamp to illuminate internal body passageways.

1

Question 8 An endoscope uses laser light to stop bleeding and to cut away and remove undesirable growths in body passageways.

1

Question 9 Endoscopy: C. Visible. thermography: B. Infra red. X-ray: A. X-rays.

1 1 1

Question 10 Microwaves are electromagnetic radiation and are absorbed by water / fat / oil molecules in body cells which can create a heating effect on them.

1 1

Detailed Study 3: Energy from the Nucleus Observation Attraction between all objects in the universe.

Force responsible Gravity.

Holding the atom together. Weak nuclear.

Question 1

Holding the nucleus together. Strong nuclear.

1 1 1

Question 2 A. 2 Question 3 D. 2 Question 4 The process is called “nuclear fission”.

If ‘necking’ occurs, electrostatic forces of repulsion will be greater than the strong nuclear forces at this point and the nucleus will ‘fission’.

1 1 1

Question 5 Mass number balance: LHS 239 RHS 237 mass number difference = 2 number of neutrons = 2

1 1


Question 6 Answer: B 2 Question 7 Loss or gain of neutrons affects mass number only.

Since the mass number changes from 238 to 239, there is only one neutron involved.

1

Question 8 Loss or gain of beta particles affect the atomic number. The atomic number changes from 92 to 94; so two beta particles are involved.

1

Question 9 Nuclear fusion occurs at a high temperature. The high temperature for fusion of the fuel must be maintained for some time. The cost of producing and maintaining this high temperature is very high and would exceed the revenue from such a process.

1

1

Question 10 Advantages: no radioactive waste problem in their operation Deuterium (from sea water) is a relatively abundant fuel source.

1 1

End of Suggested Answers


unit 1 physics lisachem 2008

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